A centrifugal compressor which is a rotary machine allows gas to pass through a rotating impeller in a radial direction and compresses the gas using a centrifugal force generated at this time. The centrifugal compressor is used, for example, in a petrochemical plant, a natural gas plant, or an air separation plant.
As the centrifugal compressor, a single-shaft, multi-stage type centrifugal compressor having a structure in which an impeller which compresses gas is attached to a single shaft, and an accelerator-embedded centrifugal compressor (hereinafter, referred to as a geared compressor) having a structure in which impellers are attached to the shaft ends of a plurality of driven shafts, are known. A type of geared compressor which compresses gas using a plurality of compressing parts having impellers provided at the shaft ends of a plurality of driven shafts is known.
In PTL 1, a geared compressor in which a pinion gear is disposed on the upper side of a gear wheel attached to a driving shaft is described. In order to prevent drain oil discharged from the bearing of the pinion gear from falling on the gear wheel, the geared compressor includes covers provided on both sides of the bearing corresponding to the pinion gear disposed on the upper side.